Research from the Rotunda Hospital in Dublin has found the chances of women getting pregnant over the age of 40 drop rapidly.
A review of the Human Assisted Reproduction clinic at the hospital shows women aged between 43-45 have less than half the chance of getting pregnant (5.04%) than those aged 40-42 (12.5%).
The research, which covers a 16-year period, also found that those in their mid-40s who do get pregnant have a substantially higher risk of losing their baby than those in the younger group.
It comes as the proportion of women over 40 using the clinic's services has risen from 7% in 1997 to 20% in recent years.
Authors of the report, embryologists Dr Linda O' Shea, Dr Ciara Hughes and Dr Ed Mocanu said that attempting to become pregnant by using donated eggs is a "very promising option" for women over 40.
Dr Mocanu warned however that people need to be aware that fertility is a finite entity and should be prioritised to avoid difficulties.
"IVF in itself cannot fix a problem," he said.
"Fertility should be high on everybody's agenda early in their career, mainly because it's a finite entity.
"One can have the power to earn or buy a house at any age, but in terms of fertility, there is only a block of time when a women can conceive."